If your ice hasn’t melted already, remove the ice and place the wet napkin behind your knee, bending your knee to fold over the napkin to keep it in place. When the cool disappears, repeat behind other knee

Re-wet your napkin with ice or cold water and drape it across the back of your neck, making a cool scarf

Let me know how these work for you and what other cool body-tricks you know of to cool yourself down in the heat!